| CRS Decorators Limited | Construction | 2021 |
| Crucial Point Media Limited | Wholesale & retail | 2015 |
| Cryolec Technologies Ltd | Manufacturing | 2022 |
| Crystal Clear EAR Clinic Ltd | Health & social care | 2022 |
| Crystal Marine Interiors Limited | Manufacturing | 2021 |
| Crystal Moon Emporium & Holistic Wellbeing CIC | Health & social care | 2021 |
| Crystal Moon Emporium Ltd | Wholesale & retail | 2021 |
| Crystal Security Trustee Limited | Extraterritorial | 2015 |
| Crystaledge Solution Ltd | Professional & scientific | 2025 |
| CS Building and Electrical Services Ltd | Construction | 2022 |
| CS Walker Developments Ltd | Construction | 2025 |
| CSM Trade NE Ltd | Construction | 2023 |
| CSS Electrical & Mechanical Limited | Construction | 2021 |
| CT Automotive Group PLC | Manufacturing | 2016 |
| CT Site Services (North East) Limited | Construction | 2017 |
| CTB Properties (NE) Limited | Real estate | 2025 |
| CTL Demolition and Dismantling Ltd | Construction | 2020 |
| Cube Exhibitions Ltd | Administrative & support | 2019 |
| Cultural Development North East CIC | Arts & recreation | 2023 |
| Culture Across Borders Nigerian Heritage CIC | Education | 2025 |
| Culture Care North CIC | Public administration | 2022 |
| Culture Quarter Ventures Ltd | Hospitality | 2016 |
| Cultured Digital Ltd | Information & communication | 2018 |
| Cummings and Ayre Fencing and Decking Ltd | Construction | 2016 |
| Cummings Architects Limited | Professional & scientific | 2015 |
| Cunningham and Wilkinson Ltd | Construction | 2019 |
| Cunninghams Rentals Ltd. | Real estate | 2024 |
| Cups and Cakes CIC | Hospitality | 2023 |
| Cups of Sunnah Ltd | Health & social care | 2024 |
| Curo Modular Services Ltd | Professional & scientific | 2017 |
| Current Ltd | Manufacturing | 2020 |
| Curtech Consultancy Ltd | Information & communication | 2023 |
| Curvaceous Couture North East Ltd | Wholesale & retail | 2017 |
| Custom Design Rosettes Ltd | Manufacturing | 2025 |
| Custom Flooring Ltd | Construction | 2021 |
| Custom Properties (North-East) Ltd | Real estate | 2024 |
| Cuthbert Enterprises Ltd | Transport & logistics | 2025 |
| CV Barbering Ltd | Other services | 2025 |
| CV Joinery Ltd | Construction | 2021 |
| CW Trading Holding Ltd | Wholesale & retail | 2025 |
| CWH Wind Ltd | Manufacturing | 2025 |
| Cwtproperty Ltd | Real estate | 2024 |
| Cyber Fits Solutions Limited | Information & communication | 2025 |
| Cyberchap Ltd | Professional & scientific | 2018 |
| Cyberwhite Limited | Information & communication | 2018 |
| Cykaido Holdings UK Limited | Financial services | 2025 |
| D & H Jewellers Limited | Extraterritorial | 2014 |
| D & J Hayes Property Company Limited | Real estate | 2023 |
| D & S Contracts (NE) Ltd | Construction | 2016 |
| D & S Motors Sunderland Ltd | Wholesale & retail | 2019 |
| D a C IT Solutions Limited | Information & communication | 2013 |
| D and D Locums Ltd | Health & social care | 2014 |
| D and S Properties Worldwide Ltd | Real estate | 2023 |
| D Clark Security Ltd | Administrative & support | 2014 |
| D D Recovery Ltd | Wholesale & retail | 2024 |
| D Holden Property Ltd | Real estate | 2024 |
| D Howey Locums Ltd | Professional & scientific | 2014 |
| D Knott Limited | Professional & scientific | 2016 |
| D Potts Electrical Engineering Ltd | Mining & quarrying | 2010 |
| D Potts Properties Ltd | Households | 2016 |
| D!Ngo Ltd | Arts & recreation | 2023 |
| D&A Peart Property’S Ltd | Households | 2025 |
| D&D Kids Ltd | Wholesale & retail | 2024 |
| D&J Damp Proofing Ltd | Construction | 2026 |
| D&N Property Developments (NE) Ltd | Real estate | 2023 |
| D&S Holdings Limited | Real estate | 2026 |
| D'Arce Security Ltd | Administrative & support | 2023 |
| D'Koya Ltd | Health & social care | 2025 |
| D. & N. Longstaff & Co. Limited | | 1979 |
| D.B Motors NE Ltd | Wholesale & retail | 2025 |
| D.Holling Limited | Health & social care | 2026 |
| D.Parker Renewable Services Ltd | Construction | 2024 |
| D1 Inspection Services Ltd | Professional & scientific | 2011 |
| D20 Bar Ltd | Hospitality | 2022 |
| D3Y Holdings Limited | Other services | 2026 |
| DA and SK Limited | Wholesale & retail | 2023 |
| DA Fuska Limited | Information & communication | 2025 |
| DAE Foods Ltd | Wholesale & retail | 2024 |
| Dailyclever Projects Limited | Real estate | 1993 |
| Dairo Logistics Limited | Transport & logistics | 2026 |
| Daisbox.Com Global Ltd | Wholesale & retail | 2024 |
| Daisy Rose Law Limited | Professional & scientific | 2021 |
| Dale Hardy Multimedia Ltd | Arts & recreation | 2020 |
| Dalton Old Pump House Ltd | Hospitality | 2020 |
| Dalyan Villa Owners Ltd | Administrative & support | 2009 |
| Damen Canavan Limited | Construction | 2016 |
| Damsells Properties Ltd | Real estate | 2024 |
| Damtech Limited | Information & communication | 2009 |
| DAN Smith Technology and Consulting Ltd | Information & communication | 2021 |
| Danamics Ltd | Information & communication | 2012 |
| Dance Events Management Ltd | Arts & recreation | 2014 |
| Dance JAM Ltd | Arts & recreation | 2012 |
| Dandelion Strategies CIC | Professional & scientific | 2021 |
| Dane Luke Commercials Ltd | Real estate | 2026 |
| Dane Luke Property Developments Limited | Real estate | 2025 |
| Dane Williamson Ltd | Hospitality | 2025 |
| Daneth Resources Limited | Administrative & support | 2022 |
| Dang Media Company Ltd | Professional & scientific | 2021 |
| Daniel Carr Rope Access Ltd | Manufacturing | 2023 |
| Daniel L Barber Ltd | Other services | 2026 |